Aeromonas (A) gum and Erwinia (E) gum are acidic heteropolysaccharides, which exist in water as expanded chains caused by the electrostatic repulsion between the charged groups. A modified approach, which was suggested to estimate miscibility of stiff polymer in our previous study, was used to determine miscibility parameter mu for blends between A gum or E gum with other polysaccharides, by using viscometry in aqueous 0.1M NaCl solution. When weight ratios of E gum/pectin were in the range of 3:7 similar to 7:3, the blends in aqueous solution are miscible. The blends of A. gum/xanthan, A gum/pectin, and E gum/xanthan in aqueous solution are obviously immiscible. When the weight fraction (w(2)) of A gum or E gum in the mixture solution is 0.7, the mu predicts that the miscibility of blend films was on the order of E gum/pectin > E gum/xanthan > A gum/pectin > A gum/xanthan. These results are in good agreement with those observed by scanning electron microscopy and Fourier transform IR.